AFP - Disappointed with the Orange Revolution's failure to bring change, Ukraine on Sunday voted in presidential polls set to be led by the pro-Russia Viktor Yanukovich at the expense of his West-leaning rivals.

Yanukovich has a lead of around 10-15 percent in opinion polls over his nearest challenger, the charismatic Prime Minister Yulia Tymoshenko, but with 18 candidates standing the election appears certain to require a second round.

The failure of Orange Revolution figurehead and 2004 winner President Viktor Yushchenko to usher in a new era in the country of 46 million bridging the EU and Russia has left Ukrainians deeply disillusioned.

Yushchenko, who has warned Ukraine can "say goodbye to democracy" if either Yanukovich or the prime minister wins, is expected to record a dismal single digit rating and be eliminated in the first round.

Yanukovich, a former mechanic jailed for theft in the USSR, was ingloriously beaten in 2004 when the Orange Revolution street protests forced a re-run of presidential polls marred by mass vote-rigging in his favour.

Polls opened at 0600 GMT and were to close 12 hours later, with exit polls expected to give the first indication of trends. The run-off vote is scheduled for February 7.

Tymoshenko, famed for her peasant-style golden hair braid, is seen as more in favour of EU integration than Yanukovich but has also played up her close ties to Russian strongman Prime Minister Vladimir Putin.

The bitter campaign saw the shady pasts of the candidates once again dredged up.

Yanukovich was jailed twice in the Soviet era for theft and assault, though the convictions were erased in the late 1970s. Tymoshenko herself was briefly detained in 2001 on smuggling charges that were later quashed.

"The electorate who took part in the Orange protests are disappointed that the majority of their expectations have not been fulfilled," said Volodymyr Fesenko, director of the Penta centre for political studies in Kiev.

"Increasingly, voters have a critical attitude to all politicians. They want to see new faces."

The level of cynicism in Ukraine is such that one local politician is even standing under the name of Protivsikh (Against Everyone) while a website appeared last week offering voters the chance to auction off their votes.

Yanukovich should win around 40 percent of the vote in the first round and Tymoshenko 23 percent, according to the latest polls by the Kiev International Institute of Sociology.

Third place is expected to go to businessman Sergiy Tigipko, who appears to have made a late surge and is given an outside chance of springing a first round upset.

"I am voting with a sense of disenchantment," said Dmytro Rudovsky, the head of a small state-owned enterprise, as he cast his vote in snow-blanketed Kiev, saying he would nonetheless vote for Tigipko.

Andrew Wilson, a Ukraine expert with the European Council on Foreign Relations, said the size of the gap between Yanukovich and Tymoshenko would be crucial in the first round.

"Less than 10 percent and Tymoshenko is confident she can close it in the second round. 10-15 percent and the election will be close. More than 15 percent is difficult," he said.

Yushchenko and Tymoshenko were comrades-in-arms in the Orange Revolution but later became sworn enemies, their relationship poisoned by a perennial power struggle and mutual accusations of criminal wrongdoing.

Since 2004, Yanukovich has sought to reinvent himself with the help of Western PR strategists and to show he is not a servant of the Kremlin but a defender of Ukrainian interests.

He has also sought more support in the country's Ukrainian-speaking west -- traditionally the heartland of Tymoshenko and Yushchenko supporters -- while holding on to his powerbase in the Russian-speaking east.